Newsletter

Athens is drier and hotter than it was not so long ago, according to new climate norms released by the National Oceanic and Atmospheric Administration, or NOAA.

Updated every 10 years by the federal agencies, the climate normals are 30-year daily, monthly and annual averages for rainfall, temperature and a few other weather measures that meteorologists use to gauge how wet, cold, dry or hot the weather is.

The latest normals are based on the years 1980-2010, dropping out the relatively cool, wet decade of the 1970s, which was part of the previous 30-year normal, and adding the much hotter and drier first decade of the 21st century, said Georgia state climatologist David Stooksbury, a professor in the University of Georgia’s Faculty of Engineering.

As a result, “normal” annual rainfall for Athens is now 46.33 inches, down an inch and a half from 47.83 inches in the previous set of normals, issued in 2000, and down by 3.4 inches from what was considered normal in 1990.

The average daily temperature in Athens is now 62.6 degrees, up 1.4 degrees in just 10 years.

Stooksbury says you can’t read too much into the new normals.

“You’re only taking 30-year snippets,” he said, which is just the blink of an eye for climatologists, who think in time scales of hundreds and thousands of years.

“The 1970s were extremely cold, so we expected to go up. Adding one of the driest and warmest decades ever recorded (the 2000s), you’d expect that kind of change,” Stooksbury said.

And NOAA has changed slightly the statistical methods it uses to calculate the averages, he said.

But the new normals for Athens and the rest of the U.S. are also one more demonstration that global warming proceeds, said UGA climate researcher Marshall Shepherd.

The new temperature normals are higher for almost all of the United States, especially the northern Midwestern states, where average January lows are up by 4 degrees.

“It’s a clear demonstration that much of the United States has warmed, and even in the Southeast,” Shepherd said.

Parts of the Southeast, including Georgia, actually got cooler in much of the 20th century, while other parts of the world were warming. But now that trend seems to have reversed, he said.

It’s hard for most people to get excited about a temperature change of a degree or two in a decade’s time, he said, or average rainfall dropping 3.4 inches in 20 years’ time, as it has in Athens.

Evidence is building up that those seemingly little changes may be producing much bigger changes in the world’s ecosystems and weather systems, he said — bigger and longer droughts, bigger and more frequent floods, and more hurricanes are also becoming “normal.”

Scientists are seeing birds and animals move to higher altitudes and latitudes as the changing climate alters the habitats they are adapted to.

“Those are the things where we can see the impacts — in terms of response to these changes,” Shepherd said.

Average ocean temperatures are also rising, increasing the likelihood of hurricanes, he said.

“Seventy-eight vs. 80 can be the difference between Irene fizzling and Irene blossoming,” Shepherd said.